Projectile munition having a shell and a fragmentation hammer block

ABSTRACT

A munition in the form of a projectile contains a shell engaged in a ferrule constituting a hammer block. The assembly is accommodated in a cylindrical plastic casing having the diameter of the barrel of a weapon for which the munition is intended. The shell has a body portion and a tip at its front end. The body portion has a diameter which does not decrease from the rear toward the front end, and a zone having a locally increased cross-section close to the shell front end. A recess in the hammer block has a shape complementary to the shape of the shell body and constitutes a bearing support for the shell. The region of the hammer block occupied by the shell zone of locally increased cross-section has a cross-section smaller than that of the latter. Defined rupture initiators starting at the front edge of the hammer block cause rupture of the hammer block into pieces of defined number and dimension at the moment the projectile penetrates a target and the hammer block passes over the shell zone of locally increased cross-section.

[0001] The present invention relates to a munition having a projectile formed by a shell engaged in a ferrule constituting a hammer block, this assembly being for its part accommodated in a cylindrical casing made from plastics material having the diameter of the barrel of the weapon for which the munition is intended.

[0002] The invention proposes the development of a munition of the above-mentioned type in order to increase the effectiveness of the projectile by the impact of the hammer block whilst avoiding uncontrolled breaking up of the projectile.

[0003] To this end the invention relates to a munition as claimed in claim 1,

[0004] The munition is very effective relative to the known munition since the fragmentation of the hammer block into sub-projectiles at the moment of impact considerably increases the impact surface area and thus the effectiveness of the projectile whilst avoiding uncontrolled breaking up of a part of the projectile, that is to say the hammer block. As the hammer block has notches forming rupture initiators in predetermined positions, rupture of the hammer block takes place along the notches resulting in fragments which correspond in number to the rupture initiators and have the desired mass.

[0005] The opening and the rupture of the hammer block take place at the moment of impact, when the tip of the shell encounters the target which retards it. The hammer block, which is slightly set back since it does not start until after the tip of the shell, pushes the shell whilst continuing to advance under the effect of its kinetic energy in order to pass over the zone with a locally increased cross-section and to open progressively, then to split when the rear part of the hammer block, which has a cross-section distinctly smaller than the cross-section of the zone with a locally increased cross-section of the shell, arrives at this level.

[0006] Advantageously the annular bead of the body of the shell is preceded by a conical sector. It is also interesting that the zone with a locally increased cross-section of the shell is a conical shape flared in the direction of the tip.

[0007] The present invention will be described below in greater detail with the aid of different embodiments which are shown in schematically in the accompanying drawings, in which:

[0008]FIG. 1 is an axial section of a projectile according to the invention,

[0009]FIG. 2A is a view on an enlarged scale of a first embodiment of a shell according to the invention,

[0010]FIG. 3A is a view on an enlarged scale of a hammer block associated with the shell of FIG. 2A,

[0011]FIG. 2B is a view on an enlarged scale of another embodiment of a shell according to the invention,

[0012]FIG. 3B is a view on an enlarged scale of a hammer block associated with the shell of FIG. 2B.

[0013] In the present description the expressions front/rear refer to the direction of displacement of the projectile.

[0014] According to FIG. 1 the invention relates to a munition composed of a case 1 with a base 2 and a fuse 3, containing a projectile 4 above a tamping layer 5 and a powder charge 6. The inner projectile 4 is formed by a shell 7 placed in a hammer block 8 constituting the internal projectile and the assembly is accommodated in a cylindrical casing 9 having substantially the same diameter as the barrel of the weapon intended to fire this projectile The casing 9 is a part made from plastics material into which is inserted the sub-assembly formed by the shell 7 and the hammer block 8.

[0015] According to one embodiment, the casing 9 is composed of a front part closed by a stopper. These two parts are not distinguished in FIG. 1.

[0016] The external periphery of the casing 9 has ribs 91 in order to facilitate the guiding of the projectile in the barrel and the front end is in the shape of a cap 92 covering the tip of the shell.

[0017] At the moment of firing, the projectile formed by the parts 7, 8. 9 leaves the case 1, propelled by the powder charge 6, and on impact the casing 9 opens to allow the assembly 7, 8 to come out.

[0018] The shell 7 has a body 71 and has a tip 72 at the front. The body ends close to the front in a zone 710 with a cross-section distinctly increased relative to that of the other parts of the body 71 of the shell. These other parts have a cross-section which does not increase from the rear towards the front, that is to say it increases or remains constant.

[0019] The shape of the recess 81 of the hammer block 8 corresponds to that of the body 71 of the shell. At its front end the recess 81 has an annular clearance 811 to receive the zone with the increased cross-section 710 of the shell 7.

[0020] The hammer block 8 also has slots or notches 82 which constitute rupture initiators for the hammer block 8, permitting it to slide over the zone with the distinctly increased cross-section 710 of the shell 7 at the moment of impact of the projectile against the target.

[0021] As it slides over this zone 710, the hammer block 8 opens at the level of the slot 82 and then tears in the extension of these slots in order to fragment into pieces according to the positioning of the slots 82. The slots 82 are preferably distributed regularly over the periphery of the hammer block 8. The number and the arrangement of the slots are chosen in order to obtain the desired fragments and consequently the desired effect on impact (more or less substantial spreading of the fragments whilst avoiding their breaking up in the target).

[0022] The zone with the distinctly enlarged cross-section 710 of the body of the shell creates a wedge effect for the ferrule whilst the other surfaces of the shell of which the cross-section increases from the rear towards the front principally constitute bearing surfaces which participate in the transmission of the kinetic energy of the hammer block to the shell.

[0023]FIG. 2A shows a first embodiment of the shell 7A. This shell is composed of a body 71A and a tip 72A.

[0024] The tip 72A is in the shape of a truncated cone and it joins the body 71A by a collar 710A of diameter F constituting a zone having a diameter distinctly increased relative to the diameter of the other parts of the body 71A.

[0025] At the rear of the zone 710A is located a cylindrical section 771A and finally a rear end 712A in the shape of a truncated cone reducing towards the rear.

[0026] Generally speaking, the cross-section of the body 71A does not reduce from the rear towards the front. It increases to the level of the section 712A, then the cross-section remains constant in the section 711A and finally the cross-section increases distinctly in the part 710A.

[0027] This shell is intended to be associated with the hammer block 8 of FIG. 3A. This hammer block is in the form of a ferrule with a recess 81A in which the shell 7A engages as is shown in a general manner in FIG. 1.

[0028] The recess 81A of the hammer block 8A has a cross-section adapted to the cross-section of the body of the shell 7A at the level of the zone 710A and the other parts of the body 71A.

[0029] This recess 71A has at its front end a set-back annular part 81A intended to receive the zone 710A with a locally increased cross-section, then the recess continues as a cylindrical section 812A having an internal diameter MM which is distinctly less than the diameter F of the zone with a locally increased cross-section 710A. Finally, in its rear part the recess has a segment 813A in the shape of an inverted truncated cone with the small base turned towards the rear.

[0030] The hammer block 8A is equipped with longitudinal slots 82A which constitute rupture initiators. These slots start at the level of the front edge 83A of the hammer block 8, are distributed on the periphery and occupy a certain part of the total length of the ferrule of the hammer block.

[0031] In the example shown in FIG. 2B, the ferrule has four slots 82A distributed in an equiangular manner, two slots are located in the plane of the drawing and the third slot which is visible in this section appears at the rear, the fourth being located in front of the drawing plane.

[0032] The materials constituting the hammer block 8A and, generally speaking, the hammer blocks within the scope of the invention, are relatively brittle materials such as bronze, brass or steel, so that at the moment of impact, when the projectile strikes the target, initially the hammer block 8A pushes the shell 7A and communicates some of its energy thereto, then the shell 7A is retarded and the hammer block 8A slides over the shell and in particular over the zone with a locally increased cross-section 710A. The lateral walls of the ferrule of the hammer block 8A part and at the moment when the cylindrical part 812A of the recess passes over the zone with a locally increased cross-section the notches 82A which constitute the rupture initiators produce the rupture of the rear part of the ferrule in the extension of the rupture initiators. Thus in the case of this example the ferrule of the hammer block 8 separates into four sub-projectiles which disperse in the target around the trajectory of the shell 7A. This number of sub-projectiles is given only by way of example.

[0033]FIG. 2B shows another embodiment of a shell 7B. This shell is likewise composed of a body 71 b and a tip 72B at the front. At the junction between the tip and the body there is a zone with a locally increased cross-section 710B having a diameter F which is distinctly greater than the diameter of the other parts of the body 713. As previously, the cross-section of the body 71B does not increase from the rear end 712B as it passes through the intermediate part 711B and the front part 713B. This front part of the body has the shape of a truncated cone, the part 711B is of cylindrical shape and the rear end 712B likewise has the shape of a truncated cone.

[0034] This shell 7B is intended for the hammer block 8B of FIG. 3B. This hammer block is largely identical to that of FIG. 3A, differing therefrom in the shape of the part 813B of the recess 81B. This part 813B has the shape of a truncated cone corresponding substantially to the truncated cone shape 713B of the shell 7B. In this hammer block 8B the front of the recess 81B is likewise occupied by a peripheral channel 83B to receive the zone with a locally increased cross-section 710B of the shell 7B Towards the rear, the recess 81B is continued simply by a cylindrical part 81B and the rear is not conical. In this case the part in the shape of a truncated cone 712B of the shell 7B extends beyond the rear of the hammer block 8B. 

1. A munition comprising a projectile comprising: an assembly comprising a shell engaged in a ferrule constituting a hammer block, said assembly being accommodated in a cylindrical casing made from a plastic material, said casing made having the diameter of the barrel of a weapon for which the munition is intended, wherein the shell comprises a body and a tip at its front end, the shell body having a diameter which does not decrease from the rear toward the front end, and a zone having a locally increased cross-section close to the shell front end, the hammer block engages the shell along a recess in the hammer block having a shape complementary to the shape of the shell body, which recess constitutes a bearing support for the shell in the direction of the hammer block facing toward the shell, the cross-section of the hammer block at the part occupied by the shell zone of locally increased cross-section being smaller than the cross-section of said shell zone, the hammer block comprising defined rupture initiators starting at the front edge thereof and adapted to cause rupture of the hammer block into pieces of defined number and dimension at the moment the projectile penetrates a target and the hammer block passes over the shell zone of locally increased cross-section.
 2. The munition as claimed in claim 1, wherein the shell zone of locally increased cross-section comprises an annular bead, and the hammer block has an annular recess at its front edge which is open toward the front and receives the annular bead.
 3. The munition as claimed in claim 2, wherein the shell annular bead is preceded by a conical sector forward of the annular bead.
 4. The munition as claimed in claim 1, wherein the shell zone of locally increased cross-section has a conical shape flared in the direction of the shell tip. 